• Geomechanics and Engineering
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• v.23 no.1
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• pp.39-50
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• 2020

In order to understand the shear mechanical properties of the interface between clay and structure and better serve the practical engineering projects, it is critical to conduct shear tests on the clay-structure interface. In this work, the direct shear test of clay-concrete slab with different joint roughness coefficient (JRC) of the interface and different normal stress is performed in the laboratory. Our experimental results show that (1) shear strength of the interface between clay and structure is greatly affected by the change of normal stress under the same condition of JRC and shear stress of the interface gradually increases with increasing normal stress; (2) there is a critical value JRC_cr in the roughness coefficient of the interface; (3) the relationship between shear strength and normal stress can be described by the Mohr Coulomb failure criterion, and the cohesion and friction angle of the interface under different roughness conditions can be calculated accordingly. We find that there also exists a critical value JRC_cr for cohesion and the cohesion of the interface increases first and then decreases as JRC increases. Moreover, the friction angle of the interface fluctuates with the change of JRC and it is always smaller than the internal friction angle of clay used in this experiment; (4) the failure type of the interface of the clay-concrete slab is type I sliding failure and does not change with varying JRC when the normal stress is small enough. When the normal stress increases to a certain extent, the failure type of the interface will gradually change from shear failure to type II sliding failure with the increment of JRC.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.1
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• pp.39-50
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• 2013

This study estimates the measurements required to make garments but omitted from Size Korea 2010. Before the estimation of the measurements, the differences of the measurement methods were reviewed through previous research related to clothing construction and various measurement protocols that include previous Size Korea 2010 projects and ISO. The research target was 308 females aged 20 to 30 who lived in Seoul and the surrounding Gyeonggi province. A total of 43 measurements were obtained by the direct measurement method and analyzed in this study. In addition, 17 measurements which differ from the measurement method were also measured directly. These 17 measurements items were waist height, waist back height, waist height natural indentation, body rise, rise length, waist back length 1 & 2, posterior shoulder length 1 & 2, arm length 1 & 2, upper arm circumference 1 & 2, elbow circumference 1 & 2, and waist circumference 1 & 2. To analyze the differences in measurements, the subjects were divided into 2 age groups (20's and 30's). The results were as follows: First, there were big differences in stature, waist height, shoulder length, total length, and neck shoulder point to breast points by age groups; however, there were no differences in 17 measurement (such as shoulder angles) by age groups. Second, it was determined that 'waist circumference 1 & 2', 'waist back length 1 & 2', 'arm length 1 & 2', 'elbow circumference 1 & 2', 'upper arm circumference 1 & 2' and 'body rise & rise length' had significant differences by measurement methods in the entire group as well as each age group. Third, the values of 8 measurements omitted from Size Korea 2010 were estimated using similar measurements. The results of the correlation analysis were utilized to select reasonable independent measurements. Finally, 10 regression equations were obtained by regression analysis; subsequently, these will be useful for estimation of omitted measurements in Size Korea 2010.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.2
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• pp.155-162
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• 2012

Recently, building of long span bridge is increasing and cable stayed bridges have large portion in civil projects. As the spans of bridges become longer, steel cable-stayed bridges have been constructed mainly for slim structure. But in many case, pylons are constructed by concrete for the stability of structures and the economy. Concrete is greatly influenced by the long-term behavior like creep and drying shrinkage, so analysis of stress redistribution and structural change in construction is required. In this study, as a cable stayed bridge with concrete pylon, Incheon Bridge is analyzed by nonlinear FEM analysis program RCAHEST. Through this analysis, time dependent effect of concrete pylon to whole cable stayed bridge system is studied.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.155-161
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• 1999

The land reclamation area of Saemangeum(Kunsan) is located between 126$^{\circ}$10' E~126$^{\circ}$50' E and 35$^{\circ}$35' N~356$^{\circ}$05'N at the western coast of the Korean peninsula. The are many small islands including extensive areas of semi-diurnally flooded and dewatered tidal flats. The reclamation area of Saemangeum has a range of 5.6m spring tide and the maximum tidal current speed is about 1.41m s-1 in ordinary spring tide. Most of the sediments deposited on the tidal flats are transported from the Geum river, the Manjyung river and The Dongjin river. The soil in this area consists of silty sand with the depth of 10m to 30m . The wind in winter is strong from the direction of northwest. In the past twenty years, land reclamation projects for agricutural purpose or industrial cocmplex have been mostly implemented along the western coast of Korea. Saemangeum coastal area is being constructed the33km sea dike and 40, 100ha reclamation area. The purpose of this study is to find the residual circulations in four seasons after the dike construction by a robust diagnostic and prognostic numerical model. Heat flux at the sea surface in January ,May , August , October was asopted on the basis on the daily inflow of solar radiation at the earth surface, assuming an average atomospheric transmission and no clouds , as a function of latitude and time of year(George L.P.J.E William, 1990). The discharge from the Geum , the Mankyung and the Dongjin rivers was adopted on the basis of experience formula of river flow in January , May ,August, October (The M. of C.Korea, 1993) . Water temperature and salinity along the open boundaries are obtained from the results of field observation s.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.3
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• pp.61-71
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• 2018

The purpose of this study is to analyze the efficiencies of project management offices in large information system construction projects using the data envelopment analysis. In addition, we tried to estimate the confidence interval of those efficiencies using bootstrap DEA to give a statistical meaning. The efficiency by the CCR model is analyzed as eight project management offices are fully efficient and 22 project management offices are inefficient. On the other hand, there are 15 project management offices are fully efficient, but 15 project management offices are inefficient in the BCC model. As the result of the scale efficiencies, of the inefficient project management offices, 13 project management offices are inefficient in scale. It is possible to eliminate the inefficiency in the CCR model by improving their project performances. And, the nine project management offices showed that the inefficiency was due to pure technical efficiency, and these companies should look for various improvements such as improvement of project execution system and project management process. In order that the inefficient project management offices be efficient, it is analyzed that more efforts must be made for on-budget and on-time as a result of examining the potential improvement potentials of inefficient project management offices.

• Korean Journal of Plant Taxonomy
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• v.37 no.3
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• pp.309-321
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• 2007

Korea national arboretum has worked with the plant taxonomic society of Korea to make the first fully electronic floristic checklist in Korea. The result is an ever-expanding online plant name index containing scientifically authorative, up-to-date information on the approximately 7,000 taxa including cultivars. With 37 contributing taxonomists, KPNI is the largest collaborative research projects ever assembled in Korea. A comprehensive database model for the taxonomic data from literature and other sources is presented, which was devised for the Korea National Plant Index database project (KPNI). Gwangreung database model is based on an approach using entity-relationsip diagram. It encompasses taxa of all ranks, nothotaxa and hybrid formulae, cultivars, full synonymy, basionyms, Korean name, and other nomenclatural information. Ths paper presents an analysis of KPNI work processes and an overview how we are approaching the construction of Gwangreung databaese model. It can help the system engineers of other biological information systems to develop their database based on the accurate and integrative taxonomic database.

• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.31-38
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• 2011

Turnkey and alternative-design contracts was introduced operation in the country from january 2004 to February 2010. this was introduced operation. The selecting method of contractor for turnkey projects has being operated by an open forum type that consists of technical committee and appraisal committee in an integrated design approach deliberations. But to improve the operation of the problems, the government is operating design review committee consisting of the central, local and special design advisory committee in march 2010. But this system has also been suggested as still problems, too many contracts by large companies, increasing of design cost and excessive competition. This study is intended to contribute that turnkey and alternative-design contracts can be well operated in domestic construction markets. In this paper suggests some improvement methods and operational problems caused from application of an open forum type for selecting contractor of turnkey project.

• Journal of Korea Water Resources Association
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• v.46 no.10
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• pp.997-1004
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• 2013

There is imminent need to find a way to measure the recreational benefits of water so that appropriate actions can be taken to make a multi-purpose reservoir. Therefore, this study attempts to apply a choice experiment to quantifying the recreational benefits of a multi-purpose reservoir, using a specific case study of Sangkwan multi-purpose reservoir. We consider the trade-offs between price and attributes of recreational attributes for selecting a preferred alternative and derive the marginal willingness to pay (MWTP) estimate for each attribute. The results show that the MWTP for providing additional 10,000 ton of water is estimated to be 3 won per household per year. The MWTP for improving 1 level of water quality is computed to be 645.5 won per household per year. Moreover, the MWTP for providing recreation facilities is calculated to be 1,518.6 won per household per year. This study allows us to provide policy-makers with useful quantitative information that can reduce uncertainty in the decision-making process related to a multi-purpose reservoir construction projects.

• Journal of the Korean GEO-environmental Society
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• v.11 no.3
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• pp.43-51
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• 2010

In the downstream areas of the Nakdong river, Pusan clays are commonly found and thickness may reach to maximum of 100m. From geological point of view, Pusan clay are characterized as holocene clays, deposited for approximately 20,000 years ago. Recently, there have been many construction projects based on these soft ground areas. It is needed to know clearly soil properties of the areas for design and safety analysis, especially undrained shear strength of soft clays. However, Pusan clay have not been studied systematically because the clay layers are usually very deep, having high sensitivity characteristic. In this study, undisturbed UD samples obtained from the downstream areas of the Nakdong river were researched using laboratory tests (CthUE, CKcUC, CIUC, UU and UC) and in-situ tests (Field Vane, CPTu). The undrained shear strength characteristics of the samples were depicted using stress-strain relationship.

• Journal of the Korean Institute of Rural Architecture
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• v.22 no.2
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• pp.9-17
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• 2020

The ratio of the deterioration housing in rural area was 29.6%, but it was 18.3% in urban area based on a 2018 survey. In consideration of the point, this study aims to analyze the actual condition of indoor air quality in rural houses to provide basic data for improving the indoor air environment. It was investigated 15housings of Hongseong-gun, Chungchengnam-do. To investigate the correlation between indoor air quality and housing type, both the field survey of housing type and precision diagnosis of concentration of indoor air pollutants such as HCHO, TVOC, Fine dust(PM-10, PM-2.5), CO₂, Radon. The results of this study are as follows. First, according to the average value of each element of rural old housing, the construction year was distributed in 1939~2004, and 12households(80%) living in houses older than 30years have passed for about 46years. As for the housing area, more than 12houses(80%) of 60㎡ or more and 3 houses (20%) of less than 60㎡ were often living in relatively small-scale housing. Second, as a result of measuring indoor air pollutants in rural houses, substances exceeding the standard values were found in HCHO, TVOC, CO₂. Third, in the case of Fine dust and Radon, none of such factors were exceeded the standard. Fourth, there was no significant difference in indoor air quality depending on housing type in rural houses. This paper is expected to contribute to the regional development projects and effective implementation of rural policies.